Sperm counts of Western men are at a ‘shocking’ record low that it now poses a potential threat to fertility in industrialised countries, a major study found.

There has been a 59.3 per cent drop in sperm produced by men from North America, Europe, Australia and New Zealand between 1973 and 2011.

One possible cause of the decline, which shows no sign of slowing, is environmental chemicals.

Study co-leader, Dr. Hagai Levine, of the Hebrew University of Jerusalem, said the findings were ‘an urgent wake-up call.’

Levine said, “Eventually, we may have a problem, and with reproduction in general, and it may be the extinction of the human species.”

Professor Daniel Brison, of the department of reproductive medicine at Manchester University, said “the extent of the decline in this study is shocking.”

Other fertility experts warned of a “double whammy” caused by falling sperm counts and women waiting until their 30s to get pregnant.

The study, published in the journal Human Reproduction Update, found no similar decline in South America, Asia and Africa.

Co-author, Prof. Shanna Swan, from New York’s Icahn School of Medicine, said: “The fact that the decline is seen in Western countries strongly suggests that chemicals in commerce are playing a causal role.”

Exposure to chemicals in the womb, adult exposure to pesticides, smoking, stress and obesity have all been linked to falling sperm counts.